Xdelta is an application program designed to compute changes between
files. These changes (deltas) are similar to the output of the
"diff" program in that they may be used to store and transmit only the
changes between files. However, unlike diff, the output of Xdelta is
not expressed in a human-readable format--Xdelta can also apply
these deltas to a copy of the original file. Xdelta uses a fast,
linear algorithm and performs well on both binary and text files.

/usr/share/doc/libxdelta2-dev/copyright

Xdelta was designed and implemented by Joshua MacDonald.
This package was debianized by Lepied <Lepied@debian.org> on Wed, 15 Oct
1997 08:23:13 +0200.
The current Debian maintainer is LaMont Jones <lamont@debian.org>
It was downloaded from http://sourceforge.net/projects/xdelta
From the upstream AUTHORS file:
The author is Joshua MacDonald, <jmacd@cs.berkeley.edu>. The Rsync
algorithm,
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